The present invention relates to a safety device for use with a firearm, and particularly to such a safety device which is visible externally and prevents insertion of a cartridge into a firing chamber of a manually breech-loaded firearm, yet permits the action of the firearm to be fully closed while the safety device is present.
Some firearms of the breech-loading single-shot variety, particularly firearms such as the M203 Grenade Launcher which is used with the M-16 rifle of the armed forces of the United States, are somewhat unwieldy when the action is not closed. Additionally, having the breech of such a firearm open exposes both the breech block or equivalent mechanism and the firing chamber to entry of dust and other contaminants which may damage the weapon.
However, in handling firearms it is extremely important that they be in a safe condition, except when about to be intentionally discharged. Particularly when personnel unfamiliar with such weapons are being trained in their use, it is important that the weapons be made impossible to discharge, and it is desirable that such a safe condition be visually verifiable by an instructor from an appreciable distance. Furthermore, such a condition of safety should be attained easily and quickly, without disassembly of the weapon or rendering it permanently unuseable.
Additionally, it is desireable to have such a weapon in a safe condition, yet have the breech of the firing chamber fully closed and locked, in order to exclude contaminants, and to permit weapons to be handled, during training, as if they were ready to be discharged.
Prior efforts to provide a means of making a firearm safe from accidental firing without disassembly of the weapon include a chamber plugging device shown in Robbins U.S. Pat. No. 2,997,802. Robbins discloses a device useable particularly in a bolt action rifle to plug the firing chamber and interfere with closure of the bolt of such a weapon. The Robbins device, however, does not appear to be appropriate for use with certain types of single shot breech-loading weapons, and particularly does not seem suitable for use with grenade launchers, as it requires that the breech be kept open. In a grenade launcher such as the Model M203 Grenade Launcher this would apparently result in a slideable launcher tube portion of the weapon remaining moveable, which is undesirable.
Hermann U.S. Pat. No. 3,605,311 and McKinlay U.S. Pat. No. 3,089,272 disclose devices which may be locked in place in the ejection ports of shotguns to prevent insertion of cartridges and closure of the breech of such weapons. These devices, however, are not readily visible from both sides of a weapon so equipped, and may allow entry of contaminants into the mechanisms of the weapons as a result of the breech being held open.
VonMuller U.S. Pat. No. 4,384,420 discloses a replacement for the magazine of an automatic pistol which may be locked in position to prevent insertion of a loaded magazine. The VonMuller device also seems to be deficient in not being readily visible as a safety indicator from any distance.
Johnson U.S. Pat. No. 4,528,765 discloses an externally visible safety device useable with repeating firearms such as automatic rifles equipped with box-type magazines. The device disclosed in the Johnson patent, however, is not readily adaptable for use in a single shot breech loading weapon such as the M203 Grenade Launcher.
What is needed, then, is a device which will positively prevent a weapon such as a breech loading grenade launcher from being fired accidentally, and which will make it easily verifiable visually, from a considerable distance away from the weapon, that the weapon is incapable of being fired. Such a device ideally should be straightforward, inexpensive, and easy to use, and should make a weapon safe without thereby exposing internal working parts to contamination, and without preventing the weapon from being readied quickly to be fired.